Land mists are physical and meteorological phenomena related to the condensation of water. They are partially retro-controlled by the forest evapotranspiration and the emission by certain terrestrial organisms of molecules capable of nucleating water vapor into micro-droplets held in suspension by the turbulent movements of the air. The process of their formation results from the cooling of a volume of air until the condensation of part of its water vapor. The droplets produced by mists are less dense and smaller which reduces the visibility less significantly than in fog. They take the form of white cloud layers present to a certain thickness above the ground and generally appear in calm weather, during clear nights, in the absence of clouds favoring the heat radiation towards the ground.